add hwloc support
Hwloc should be used to query the topology of the node and figure out a list of areas that are available. This list should probably use a more high-level set of area types than the ones defined at the low-level. To do:
- add hwloc to autotools config
- add high-level area types and creation functions
- add function to query the topology and return a list of available areas.
- decide if query is dynamic or done at library init.